Update: A video from the People’s Daily does make it seem surprising that production would be unaffected.

A fire broke out last night at Foxconn’s main iPhone manufacturing plant in Zhengzhou, China, with the WSJ noting that it spanned several floors of the factory. Foxconn confirmed reports, but said that there were no casualties and production was not affected.

Local authorities said they are investigating the cause of the fire. The fire began in the central air conditioning fan and ventilation ducts on the roof of one of Foxconn’s Zhengzhou plants, according to a statement on the website of the Zhengzhou Airport Economy Zone.

There have been previous fires and explosions at Foxconn factories, the most serious of which was at an iPad 2 production facility in 2011, when three workers were killed and fifteen injured. That incident also had a major impact on iPad production.